Firing device or fuse for explosive projectiles.



W. S. ISHAM. mmm vivace on rus: ron Exnoslvi Psolccmcs.

PPLIBATIMI HUD AY Il WH.

Patentd Apr. 11, 1916.

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2 SHEETSSHEET 24 Patnted Apr. 11, 1916.

W. S. ISHAM.

Hama nEvlCE oa FUSE F011 EXPLoslvE PROJECTILES.

APPLCATIUN FILED MAY12.1914.

w 7H L. 0MM/u n WILLARD AS. ISHAM, OF WASHINGTON, DISTRICT 0F COLUMBIA.

FIRING DEVICE OR FUSE FOR EXPLOSIVE PROJECTILES.

Specification of Letters Patent.

Patented Apr. 11, 1916.

Application led May 12. 1914. Serial No. A838.119.

To all whom it m ay concern Be it known that I, ll'iLLAnn S. IsnAM, a. citizen of the United States, residing at ll'ashington, in the District of Columbia, have invented a new and useful Improvenient in Firing Devices or Fuses for Explosive Projectiles, which improvement is fully set forth in the following specification.

My invention relates generally to firing devices or fuses for explosive projectiles, and particularly to that class of fuses in which the fuse is designed to be placed in the point of a projectile. Certain features of the invention, however, may be used in other kinds of fuses.

The principal objects oi" the invention are to provide a fuse that will render the projectile carrying it safe to fire from high power guns, and to provide a fuse that will insure explosion of the bursting charge of a projectile at such a time with reference to the impact of'the projectile with different objects or materials against which it may strike, as to give the maximum effect upon the target against which the attack is directed.

My device is designed especially to be employed in the class of projectiles known as torpedo shells.

Among the desirable results attained by the use of my novel firing device or fuse in the torpedo shell are: (1) A shell equipped with this device will explode instantly upon makingr either perpendicular or glancing impacts with armor. such as the thick armor ot' battle ships. having sufficient thickness and resistance to break up or seriously detorm the shell. explosion thus occurring prior to. rather than after. penetration; (2) the shell explodes very quickly after making either glancing or direct impacts with less heavy armor or other metal resistances, although these `may be incapable of breaking up the shell; for example, thin armor, smoke stacks, chains. torpedo boats. etc.: (il) the shell. upon striking the water, explodes after a considerable delay, whether the shell remains in the water or ricochets.

According to the present invention a shell or similar projectile is provided with a firing or fuse device containing a burstingr charge of a relatively insensitive explosive. said charge being ordinarily adapted to explode only upon ignition by a flame, and thus to fire the relatively very large body ot' explosive constituting the bursting charge oi the shell itself. To this end a suitable time or delay train leads to the bursting charge of the tiring device. Means operable by impact or material retardation are provided for igniting this train said means being maintained incapable oi operation prior to usingr the shell, but being automatically brought, when the shell is thrown from a gun, into readiness for operation; it being impossible in any case for ignition of the charge to occur, however. until the shell is out of and at a substantial distance from the gun, the possibility of premature explosion being thus avoided.

The time train may be of any desired length. It is intended that the train as a whole shall act to transmit ignition from the impact-operable means before mentioned to the bursting charge of the firing device only in cases when the shell strikes a relatively yielding medium, such as water, and when the retardation of the shell, though appreciable, is relatively slight. When the impact is sharper, however, as when the shell meets with the resistance of metal or the like, suitably arranged mechanism acts to cut out or eliminate the ignition train wholly or in part, so far as its normal operation is concerned, permitting the impact operated ignition means to ignite the bursting charge of the tiring device directly, thus causing almost instantaneous explosion of the shell charge.

The type of operation just described 0ccurs in the device ot' the present invention when the resistance encountered by the shell is more intense than that oifered by water, but less than that otl'ered by a thick mass of metal such as the armor belt of a battle ship. lVhen the shell strikes a target of this latter type it is desirable to have the shell charge explode even more promptly than it will merely by cutting out the time train in the manner above explained. The desired result may be attained by employing in the main shell charge. or in the firing device. or in both. a quantity of a more sensitive explosive which explodes by violent shock, but only under shock of the intensity developed by impact of the shell against thick masses of metal or the like. Ordinarily where the bursting charge of the shell consists wholly or in part of such an explosive. such explosive need not be used in the firing device itself.

To show how these results are attained by means ot' the present invention. reference is had to the accompanying drawings illustrating typical emlaaliments of the broad inventive principles here involved.

In these drawings. Figure 1 is a central longitudinal section through a fuse device or tiring device constructed in accordance with the principles ot' the invention, the shell on which it is mounted being fragmentarily indicated: Fig. 2 is a similar section taken at right angles to Fig. 1; Fig. 3 is a section similar to Fig. Q. but shows the plunger revolved 90o to its tiring position; Fig. i is a detail perspective of the train cutting pin.' Fig. 5 is an end view of the plunger; Fig. 6 is an end view of the train plug; Fig. T is a central longitudinal section of another embodiment of the invention; Fig. 8 is a similar section taken at right angles to Fig. T; Fig. 9 is a plan of the device shown in Figs. T and 8; Fig. 10 is a plan. and Figs. 11 and 1:2 are sections, in ditferent positions, of tiring pin mechanism; and Figs. 13, 14 and 15 are corresponding views of a modified form of firing pin mechanism.

Referring to the drawings, Figs. 1 to G illustrate an embodiment of the invention wherein the firing device is provided with a relatively insensitive explosive charge and with a semi-insensitive charge, said charges being contained in separate compartments. The fuse stock has a head 1 and a hollow cylindrical portion :2 exteriorly threaded to engage corresponding threads in an opening in the point of a shell 3 into which the firing device ma y be screwed. Recesses 3 may be provided in the outer face of the head l to receive a spanner or other suitable wrench device. The inner portion of the fuse stock comprises a cylindrical casing l which is interiorly threaded at 5 to receive a threaded coupling sleeve (i which also engages threads on the inner surface, ot' cylinder 2, thus firmly securing together parts 2 and 4 of the fuse stock. Located within the casing 4 is a sleeve or cylinder T closed at its lower end S and open at its upper end. The upper portion ot' this cup-like member is exteriorlv threaded to engage the inner threads in casing -l. and can thus be screwed into the latter llntil the upper edges of the member T abut the lower edges of coupling member f3. chamber or tfompartment E) is thus formed to receive a` charge of a relatively insensitive explosive of which ordinary black powder may be considered typi- ^al. Explosive may be charged into chamber il through an opening provided with a suitable closure 9. lhe lower end of' the casing l is closed by means ot' a threaded cap or plug 1U; and the chamber ll thus Jt'ormed between the threaded cap and the bottom of member 7 is intended to contain a semi-insensitive explosive. Typical explosives of this character are gun cotton, carrying a large percentage, say 10 per cent.,

of water; explosive gelatin, containin a large percentage of camphor; or any ot ier suitable explosive that will be exploded by a violent shock sufiicient to seriously dei'orm or break up the shell, but which will not explode by shock when the shell strikes water or other material offering an approximately the same or less resistance. and which will not of course be exploded b v the lesser shock incident to tiring the shell from a gun. The exact degree of insensitiveness required in the explosive contained in chamber 11 is of course variable with conditions of service. depending among other things, upon the size oi shell used. the dimensions and shape oi' the chamber in which the explosive is contained. etc. As these conditions a rc well known and understood by those skilled in this art. the designing of the semi-insensitivey charge to meet any given requirement is a simple mattei'.

A convenient form of mechanism for firing the charge in chamber 9 will now be de scribed. The coupling member G is here shown having a contracted portion 12 which is interiorly threaded to receive a threaded train plug 13 which has a depending cylindrical projection 14 of less diameter. this depending portion being connected to the body oi the train plug hy a relatively thin section or neck of metal as indicated at 15. A t'use train 16 extends from the recess 17 in the train plug downwardly through the projection 1l and opens into a transverse passage 1S extending through said projection and opening at its opposite ends into the chamber t). Arranged in a central bore or passage extending axially7 of the fuse stock is a pin or plunger 19. one end Q() oi which projects beyond the head of' thc t'use stock and is best covered hermetically by a thin cover 21. The lower or inner end of this plunger. which may be ot somewhat less diameter. lits in the recess 17 ot' the train plug and is slidable therein. The. lower end ot' plunger 19 may he cut on a bevel. as shown. to provide a kind of chisel edge capable of cutting tht` thin section or neck of lnetal at l5 when the plunger 1f) is in operative position for this purpose and is driven inwardly with suliicicnt force. 'lhe pin or plunger 1f)isalsoprovided with a vent passage J2-23 opening at its lower end into recess 1T and train lt' ol' the train plug. `Extending laterally from the plunger is an angular lugl or arm 24 which has its lower surface formed to suitably engage the spiral or helical upper surface of an upwardly projecting portion 25 oi the train plug. such upward projection and helical surface extending in this instance over approximately 9U@ ot' the annular top of the train plug as shown in Fig. 6. The arm 24 of the plunger is normally supported on this sloping or helical surface in the position shown in Figs. 1 and 2. In this position the lower end of plunger 1f) is held away from the neck of metal at 15, and the plunger cannot operate to cut the delay train even il the shell` in being handled, were to receive a severe blow on its point as it might` for exalnple` in accidentally falling down an ammunition hoist.

The arm 24 fits within a notch or recess in the lower portion of a hammer member Q6 which fits loosely within the coupling sleeve 1G and around the pin or plunger 19. The arm 24 thus supports the hammer member and is locked thereto against relative rotation; consequently rotation of the hammer member compels said arm and plunger 19 to revolve therewith. The lower portion of the hammer is cnt away as shown in Figs. 1. 2. 3 and 5 so as to permit it to revolve approximately 90 from its normal or starting position. It has a percussion cap .27 seated in a` recess at its upper end. from which extends a vent passage 28 leading to vent passage 22 23 ot' the pin or plunger.

Secured as by screws 29 to the upper end of the coupling sleeve G is a disk 30 in which is mounted a tiring pin 31 at the same distance from the axis of the firing device as is percussion cap Vi. The end of this tiring pin projects inwardly or rearwardly. and the upper surface of hammer member 2G may be provided with a groove to accommodate it. Disk 3U is also provided with holes or recesses 33 and 34.- adapted to receive the end of a locking pin 35 working within a cylindrical recess provided in the hammer member 2G, said pin being normally pressed forwardly by a spring 36. In the arrangement here illustrated, the holes or recesses 253 and 31 lie on a circle of the same diameter as that on which percussion cap 2T is located; and when the parts are in the. position illustrated in Figs. l and recess 33 is directly over the percussion cap QT, a vaant space being thus provided above the percussion cap and serving as an additional sate-guard against accidentally striking the cap and setting it ofi". The recesses 33 and 3J. are arranged substantially 90@ apart to correspond with the extent ot' the sloped or helical surface on the top ot' the train plug. This arrangement therefore constitutes means for receiving the locking pin and securing the hammer and fusecutting pin or plunger 19 in proper relation with the tiring pin and with the projection J5 on the train plug.

ln the chamber U may be arranged a loose collar 3T surrounding the depending projection 14 ot' the train plug. Openings 3S arc provided in the collar to permit ready passage ot' explosive trom chambers 9 int-o the interior of the collar. and also to permit the explosion llame to pass readily from the train, or from the cap when the train is cut out, to the explosive contained in chamber 9. lt is to be understood that the space inuncdiately surrounding the cylinder I4', as well as the passage 18, may be and usually is also illed with ignitible explosive. This loose collar, although not absolutely essential, is advantageously provided to assist in breaking otl' the depending portion of the train `plug when the fuse device receives a transverse shock, as for example, when the shell strikes a glancing surface or strikes sidewise after ricochet.

In the lower chamber ll may be provided a suitable weight such as cylinder 39 to increase the shock of an oblique impact or blow due to the shell striking a heavy lnetal mass and thus to insure explosion of the semi-insensitive explosive placed in the chamber around the cylinder. The charge in chamber ll is, ot course. designed to be exploded also in the case where the shell strikes perpendicularly against a heavy metal mass. the requisite shock being developed by the sudden retardation of the shell. lt is evident that when thc charge in chamber 11 is exploded in either of the ways just mentioned. such explosion occurs independently ot' the fuse or tiring mechanism which has been described above.

The semi-insensitive explosive may be contained in a separate compartment or case as in the present instance; or it may be contained in the same comlmrtment with the insensitive charge: or. as before stated. the scmrinsensitive charge may be carried in the body of the shell itself. instead of co11- stituting a part ot' the tiring device proper. A semi-insensitive explosive may constitute the whole or any part of the shell charge propel'. ln any case. the employment of such a charge. in combination with tiring mechanism ot' the general type above described. constitutes an important part of my invention in its most advantageous embodiment.

The operation ol' the parts thus far described is sulliciently obvious from the foregoing. lVhcn the projectile starts in the gun. that is. at the instant ot' tiring the gun, the zu'ccleration ot' the shell throws the locking pin Z lmckward or inward. the setback releasing the hammer member 21" from its connection with the disk Ill). As the shell progresses, a rotation in a right-hand or clockwise direction l viewing the shell from the rear) is imparted to it by thc gun rilling. As a result. the hammer member and the pin or plunger lf) undergo. b v reason of their inertia` relative rotation to the left through 90C. the rotation being limited by the shoulder l() on the hammer member striking against the vertical face l1 of the train plug projection 25 (Fig. fl). ln order that this operation may occur with certainty, it is the disk.

advantageous to form the contacting sur faces of the arm Qt and projection 2.3 with a slope equal to or greater than the angle of friction of the two surfaces. By thus inclining the bearing surfaces in question, the reaction of the upper surface of train plug projection 27 against the lower surface of arm zl-t has a component parallel to said surfaces and tending to move arm A down the slope, and thus to revolve hammer 26 positively into operative position with caps 2T aml pin 31 alined. Other things being equal, the magnitude of this component force for a given setback pressure depends upon the angle of slope. The force may be just about sufiicient to overcon'le, and thus substantially to eliminate, frictional resistance; or with steeper slopes it may be much greater. In either case this component driving force is derived from setback pressure, being independent of. though supplementing, the effect of shell spin in producing relative rotation between the hannner and the other fuse parts. The parts having arrived in the position illustrated in Fig. 3, the cap Q2' is now in line with the firing pin 31, While the locking pin is in line with recess or hole 33 in In the meantime the arm 24- of plunger 19 has slid off the sloping surface of the train plug projection, and the beveled end of the plunger rests on the bottoln of the recess 1T at the outer or forward end of the fuse train 1li in position to cut the train at 15 when the plunger end 20 receives a blow or impact of sullicieut magnitude.

'hen the shell passes out of the gun and ceases to receive acceleration, the reaction of spring If on the locking pin 35 forces the pin forward and locks the hammer member against further rotation relative to disk ilu. lf now the projectile in its flight is retarded by any lnaterial resistance the hammer membe 'Ztlisthrown forward by its inertia and the percussion cap is forced against the tiring pin which thereupon explodes it. The flame of this explosion travels by way of passages 2S. .2 and 223 to the time train 1G and ignites the same. lf the resistance encountered by the projectile be due to its striking water, the plunger 19 will not receive sullieient impact to drive it inwardly so as to break the reduced metal section 15 and thus to break ofi' projection 14 and the lower portion of the fuse or delay train. Under the conditions assumed, therefore` this train burns for a definite period and its flame therefore, reaches the explosive in chamber 5l only after a definite delay. The flame upon reaching the explosive in chamber J ignites the charge which thereupon explodes. bursting the casing 4 and exploding the main bursting charge in the. shell. This delay occasioned by the described operation of the time fuse makes it impossible, in case the percussion cap be exploded prematurely in the gun, for explosion of the shell to occur in the fun, since the delay normally amounts to aliout a second of time, and during this delay the shell will have left the gun and will be several hundred feet away. In case the shell strikes water, this delay also permits the shell lo bury itself in the water to such a depth before exploding that it becolnes a` mine and is destructive at distances which have been determined by experiment and embodied in formulas. Furthermore, the delay also permits the shell to ricochet and travel a long distance before exploding, during which tune it may ind a target and explode by impact as hereinafter explained.

1f thc projectile in its flight strikes squarely against a thin plate of metal or other relatively hard material against which the impact is more intense than that due t0 striking water, the protruding end .20 of plunger 1S) will receive the impact and the plunger will be driven inwardly and its beveled inner end will cut the reduced metal section 15 securing projection 1l to the train plug, and the projection will thereby be broken off. In the meantime the percussion cap will have been exploded by the retardation of the shell and will send its flame through passages 2T. 22 and directly into the explosive contained in chamber t), and a much quicker explosion of the shell will result. The result will be the same even though the delay train may have been previously ignited as a result of the shell"s impact with water. The construction described thereforel provides for a delayed explosion of the projectile upon relatively moderate impact or retardation through the agency of a delay action train: and it also provides for producing almost instantaneous explosion of the projectile upon impact which is sharper or more intense. The mechanism capable ot' performing these functions is normally maintained out of operative posilion so that neither the delayed nor the more rapid explosion can be brought about accidentally by any blows or shocks to which the projectile is liable to be subjected prior to liring. For the sake of simplicity and compactness` the said mechanism is here shown as comprising but a single percussion device which may be considered to be capable of jaa-forming two distinct functions. That. is to say` it may produce delayed eX- plosion through the delay action train 16; or it may llash directly into chamber i), when the delay train llas been cut out by plunger 1H. to produce explosion almost instantly. While tbc construction here shown has peculiar advantages. it isnevertheless to he understood as illustrating merely a particularly desirable form of apparatus within the scope of the invention, which latter c0ntemplates in its broadest aspect any arrangement ot' t'use parts which is capable ot' producing both delayed and quick action explosion of the shell. but in which the parts are normally out of operative position for both typesl ot' explosion and can assume operative position only after the projectile has been lired.

It' the shell strikes thick armor, or material ollcring an equivalent resistance, with such a blow as will break up the shell or seriously lcl'orm it. the shock will be sullicieut to explode the semi-insensitive charge contained in chamber 11. It is a very important and essential t'eature ot my invention in its best embodiment, however, that the charge in chamber 11 shall also be so designed that it will not explode merely upon the lshell`s striking water. This feature makes possible new results in the art of fuse ma nufacturc. the object sought and obtained beine' practically the opposite of that which has )een the basis ot' other t'uses heretofore proposed which have been designed to permit the shell to penetrate thick armor without exploding b v the shock ot' impact.

In Figs. T. S and 9 is illustrated another t'orm ot tiring device embodying the broad principles` ot the present invention. This embodiment ot' the invention has proved satisfactory in actual practice, but I do not regard it as being so advantageous a construction as that hereinabove disclosed. Ret'erring to Figs. i'. S and 0. the fuse stock in this instance comprises a head portion 50 which is integral with a hollow cylindrical portion 5i closed at its inner end by a threaded plug or cap 5'. which may be provided with a groove 53 to accommodate a tool t'or screwing the plug into place. The outer or head portion ot' the stock is exteriorly threaded to engage threads in an opening in the point ot' the shell into which the firing device may be screwed. The projecting outer t'ace of the fuse stock may be provided with recesses 5t to accommodate a spanner or other wrench means. Located centrally in the tuse Stock is a pin or plunger 55 having an enlarged lower portion 5G titting closely in au axial bore in the 4stock head and terminating in a conical point .77. lietween the upper part of the plunger and the wall.- of the bore is a clearance space 5S which is best filled with lead. typc metal. or the like. to bermetically `seal the `ioint between the plunger and the fuse stock. n annular flange 59 in the bore normally engage the shoulder G0 ot' the enlarged portion ot the plunger.

The outer end (1l ot the plunger projects somewhat beyond the upper end of the fuse stock. In order to protect the end of the plunger trom being accidentally struck before the Shell is to be used, suitable means is provided to protect the same. In the present example, such means comprises a split collar or nut G2, each section thereof having a spur or the like 63 adapted to enter a complementary recess in the plunger. The sections of the collar or nut may be held in place by pins (i-L working in suitable bores in the fuse stock and normally held in the position shown in Fig. 7 by .springs (15. Shallow grooves` 6G are provided on the outer periphery of the split collar to receive the slightly tapered ends of the pins (H. B v this arrangement, the collar. which advantageously extends a slight distance beyond the end of plunger 55, effectively protects said end from accidental blows and locks the plunger so that it cannot be driven in by any blow or shock to which a .shell is subjected in handling prior to being tired.

The cylindrical chamber 5l of the tiring device contains both a charge of relatively insensitive explosive 67 and a charge of semiinsensitive explosive (3H. no special means being provided in this instance to separate said charges. Mechanism for tiring the insensitive charge U7 will now be described. In a general way the arrangement is similar to that described in connection with Figs. l to (i. but involves certain important modifications. .lt tuse plug (S9 secured as by screw threads 7U in a recess of the plug .12, incloses a chamber 7l and is surn'iounted by a cylindrical extension 7i terminating in a conical point 73 normally very close to the point 5T of the plunger before described. This upper portion 72 ot' the fuse plug is shown integral with the. chambered lower portion, being connected thereto by a relatively thin scction of metal at T-l. so that the projecting portion 7:2 lnay be rather readily broken off the main body of the train plug. lithin the projecting portion T2 is arranged an ignition train T5 at whose lower or rear end is arranged percussion cap 76. this percussion cap being located. as shown. in the upper wall of chamber 71. and substantially in the arti:-l thereot'. At its upper end. the train opens into a transverse passage T7 leading directly to the insensitive charge 67.

Fitting loosely within the chamber 71 is a cylindrical hammer 7U provided with an ewentrically disposed bore H0 within which a plug' Sl is slidablv arranged. The plug 81 is provided on its lateral surface with a longitudinal groove Si! which is substantially in alinement with percussion cap 7f3. From the lower end of this groove a passage 83 cxtendsl transversely into the plug S1. and this pass-age conveniently makes substantially a right angle with groove SQ. One end of a pin S4. which may conveniently be simply a headless wire nail or the like. is thrust into passage the remainder of the pin normally lying on the upper surface. of hammer member 79. It is apparent that if the plug 8l be forced downwardly from its elevated position shown in Figs. 7 and l0, the pin or nail Hl will be bent exactly at right angles to present its point projecting somewhat beyond the face of hannner 75l and directly in alinement with percussion cap TG. thus forming a firing pin.

Another arrangement for forming the firing pin is illustrated in Figs. 14 and 15 where the hammer 79 instead of normally resting on the cap or plug 5:2 is intended to remain elevated until the firing pin is to be bent into operative position. In this modification. the hammer is provided with longitudinal groove S2 and passage 83' substantially at right angles thereto, while the firing pin Si extends into the passage 83 and overlies the top of the cylindrical plug 81 which normally rests on the closing plug 52. The outer wall of cylindrical bore 80 may be slotted as at S5 to receive the outer end of the firing pin before it is bent over. It is evident that in this modification. if the hammer T9 he forced downwardly. the pin 84: will be bent as before and will present a pin projecting beyond the. face of the hammer and in alinement with the percussion cap. The operation of this modified form of the invention as illustrated more particularly in Figs. T to 13. is sufficiently clear from the foregoing description. At the moment the gun is tired the acceleration undergone by the shell forces the pins 64 back into their respective recesses. thus leaving the sections of the split collar 62 free to fiy apart as they tend to do by reason of the centrifugal force due to the spin of the shell. At the same time, member 8l, by reason of its inertia, experiences a violent set-back and is forced entirely within the bore 80, thus bending the hitherto straight pin 84 into operative position with its point in alinement with the percussion cap. The firing device is now in condition to he operated by any material retardation or impact experienced by the shell in its flight. For example. if the shell strikes water. the retardation will immediately cause forward or outward movement of hammer Tf). thus forcing the firing pin against the percussion cap and igniting train T5 which will duly ignite charge (il after a definite period of delay dcpending upon the length and chametcr of the igniting train. As before. impact of the shell with water does not produce a sufficiently intense shock to explode semi-insensitive charge (SS: and under these conditions. said charge does not explode until charge 67 is exploded as described. Furthermore. the impact of the point or nose of the firing device with water will not force projecting end G1 of the plunger inwardly. this movement being resisted by the lead or other soft metal surrounding the outer portion of the plunger and entering the locking groove 86 formed therein.

If the shell strikes squarely a comparatively thin metal plate or other object or material offering resistance comparable in degrees or intensity to that offered by a thin metal plate the impact will drive the pin or plunger 55 inwardly and the conical point 57 thereof will pass on one side or the other of the corresponding point on train plug projection 72. thus forcing the projection to one side and breaking it off. This cuts out the delay fuse train and the flame from the percussion cap flashes directly into the charge G7 and explodes both charges (37 and 68. If the blow be a glancing one, the transverse shock will be suflicient to break off projection 72 without the plunger 56 being driven inwardly, so that the delay action fuse will be cut out in a similar manner. lf now the shell strike either glancing or squarely a mass of relatively thick metal. the shock will be sufficient to explode the semi-insensitive charge ('18 immediately. entirely independently of the operation of the fuse mechanism for firing charge 67.

lVhile the constructions above described are particularly advantageous embodiments of the present invention. it is obvious that many changes in detail can be made without departing from the spirit of the invention. For example. the arrangement of means whereby the train plug projection is broken off hy the set-back of the plunger may be consideral'lly altered. Thus. in the construction illustrated in Fig. 'i'. the plunger 55H56 may he simply beveled at its lower end in a manner similar to the showing of Fig. l. instead of being provided with a conical end 5T: while the upper end of projection 72 may also simply be beveled or otherwise formed so that downward movement of the plunger will ca use a lateral thrust to he exerted on the train plug projection. It is apparent. therefore. than any arrangement will be suitable so long as setback of plunger 55 5V causes the application of force transversely to the train plug projection sullicicnt to break it ofi' the train plug at the reduced section or neck. More over. it is entirely feasible to accomplish the shortening or elimination of the delay train by entirely different means. For example. a valve or lsimilar means. arranged to be operated by impact of the shell. may be arranged to establish direct communication at the proper time between the percus- 1 sion cap and the charge to be tired. In practice. however` the arrangement of parts shown in the drawings is found to work admirably and is considered most advantageous.

ltiodifications such as those above mentioned and other changes of generally similar nature may be made within the limits of the invention and are included within the scope of the appended claims.

Although l have herein disclosed specific and particularly :ulvantageous examples ot' the invention in whieh an insensitive eharge, is employed. it is not to bel interred that sur-h eharge is an imlispensable element ot' the rombination in all eases. l believe it to be broadly new in the projeetile art to employ. in eombination with a semi-insensitive eharge` a time or delay t'use` or means t'or exploding sueh eharge operable by impact or retardation ot' insull'ieient intensity to explode sueh semi-insensitive charge by shock.

For the purposes of this invention, a semi-insensitive charge or explosive may be defined as one ot sueh eharaeter and arrangement as to be explosible by the shock due to impaet ot' the projeetile in which it is eontained against thiek metal armor or the like. but not explosible by the shoek due to impart against water. relatively insensitive explosive is to be understood as one whieh is not explosihle by shoek1 or at least not by any shock of the character en eountered in ordinary praetiee, but is usually exploded by a e: p. either direetly or through a powder train. that is. by a flame. spark. or other applieation ot' heat.

lVliat l elaim is:

l. ln a t'use t'or shell. theI eombination. with an explosive eharge and a tiring meehanism designed to explode a eap by retardation ot' the shell. ot' a vent and delay train arranged to transmit the thune ot' the rap to the explosive eharge` and means operable only upon impart ol the required intensity to shorten the delay train.

2. Firing meehanism for projet-tiles Comprising the eombination, with a t'use stonk, and a eharge eontained therein. of a pereussion deviee. a time or delay aetion train operable thereby t'or igniting said eharge. and means operable by impart to shorten the etl'eetive length otl said delay action train.

Il. ln a tiring deviee. the eombination with a delay train. otI a movable member 'apablo when in operative position oll eutting out the delay train upon impart with armor to ell'eet substantially immediate explosion ot the shell eharge. and means normally maintaining said member in inoperative position but arranged tor aetuation by motion otthe shell in flight to move said member into operative position.

l. Firing meehanism tor projeetiles eomprising the rombination. with a fuse .stork aml a delay artion train therein. ot" a plunger prolieeting beyond the end ot' the t'use stoek and arranged when driven in\ vardl.\f to eut said delay train` and means normally lor-king said plunger in inoperative position, .said means being arranged to release the plunger when the proiertile is tired.

5. Firing meehanism lor non-armorpiercing projectiles eolnprising a charge explosible h v shoek due to impact of the projeetile in flight against thick metal but not explosible by shoek due to impaetagainst water. in eombination with a charge substantially not explosible by shoek but explosible by a rap` and means for exploding the latter charge, said means being operable by impart of the projeetile in light with material otl'ering resislanee equal to or greater than that otl'ered by water.

t. ln a non-armor-piereing projectile, the eombination with a charge explosible by snoek due to impart ot' the projeetile in flight against thiek metal but not explosible by shork due to impart against water. of a rharge substantially not explosihle by shoek but explosible by a eap. and means t'or exploding the latter eharge, said means being operable hy impart ot' the projectile in Hight with material otlering resistance equal to or greater than that offered by water.

T. ln a non-armor-piercing projectile, the eombination` with a eharge explosible by shoek due to impaet ot' the projectile in flight against thiek metal but not explosible by shoek due to impart against water, ot' a eharge substantially not explosible by shoek but explosible by a eap. and a pereussion deviee for exploding the rst mentioned eharge when the projet-tile strikes water or thin metal.

H. In a non-armorpiereing projeetilc, the rombination. with a eharge explosible by shoek due to impart ot the projeetile in flight against thiek metal but not explosible by shoek due to impact against water. of means t'or exploding said ebarge. said means being operable by impart or retardation insullieient to explode said eharge by shoek.

El. ln a non-armor-piereing projeetil, the eombination. with a eharge explosible bv shoek due to impart ot' the projeetile in flight against thiek metal but not explosible by shot-k due to impart against water. of means lor exploding said eharge when the shell strikes water or thin metal. said means eomprising a pereussion deviee.

lll. ln a non-armor-piereing projeetile, the eombination with a eharge explosible by shoek due to impart ot' the projectile. in 'light against. thiek metal but not explosible by shork due to impart against water` ot a delay aetion fuse deviee arranged to be set in aetion upon impart with water and to detonate said eharge.

11. lu a projeetile. the eombination. with a ebarge explosible, by shoeik due to impact ot' the projeetilo in flight against thick metal but not explosible by shook due to impart against water, olI a delay action fuse, and a. weight arranged to eontact with said charge and to augment the effect of shock due to impact of the projectile.

1Q. In a projectile, the combination, with a delay action train, of means operable only upon impact with solid material for automatically shortening the etfective length of said train. said means being normally out ot' operative position but being arranged to be brought into operative position by motion ot' the projectile in tliglit prior to impact.

l. ln a projectile, the combination, with a delay action train. oi' means operable only upon impacty with solid material t'or automatieally shortening the ell'ective length ol' said train` said means being arranged to lie brought into operable position by motion of the projectile in flight.

14. ln a projectile. the combination. with a delay action train. arranged to be set in operation by retardation of the projectile in tligbt. of movable means for producing almost instantaneous explosion of the projectile. said means being normally ont ot operative position but being arranged to be brought into operative position by motion of the projectile in flight. i

15. ln a projectile. the combination. with a delay action train. ot' movable means tor shortening the delay train upon impact ot' the projectile. said means being operable by ohliipie or glancing impact ot' the projectile.

lt'i. 1n a. Jfuse or tiring device. the combination. with percussion mechanism` ot a niember carrying a delay l'use or train ai'ranged to be ignited by said percussion mechanism. :i portion ot' said member being adapted to be broken oil readily upon oblique or transverse impact ot' the` reijuisite intensity, whereby the ell'ective length ot' said train may be automaticaliv shortened.

1T. In a (use or firing device. the combination. with a train plug having a dela \r i'nse or train. of a movable weight arrai'iged to strike said train plug upon obliquel impact ot the requisite intensity. and therebyv to break said plug and cut out the train.

19. Firing mechanism Jt'or projectiles comprising members normally out ot alinenient` so as to be incapable of reacting but capable of enacting to produce ignition when brought into aliiieiiieiit with each other. revolnble means for bringing said members into alinement'. said means being :irranged to utilize as a revolving l'orce the setback pressure due to tiring. and a delay action train adapted to be ignited by said members. in combination with a plunger constrained to i'evolve with said revoluble means into position to he driven inwardly hy sulliciently intense impact and thus` to shorten said delay train.

10. Fuse mechanism for projectiles comprising the combination, with a fuse stock having an inclined bearing, of a rotatable hammer member supported on said bearing', and a` percussion device capable of being operated when the hammer member is rotated into proper position` the angle of inclination ot' said bearing being at least substantially as great as the :ingle of friction between the contacting surfaces.

2t). Firing mechanism l'or projectiles comprising the combination. with a i'nse stock carrying one part ol a percussion igniting device, ol'v an inclined bearing within said l'use stock, a hammer member rotatably mounted on said bearing and carrying anoiier part ot said percussion igniting dei" ze. said parts otl the percussion device being normally ont of alineinent but capable of being brought into alineinent by rotation of said hammer member on said inclined bearing relative to said fuse stock. the angle ot inclination ot said bearing being at least substantially as great as the angle of frietion between the contactiiig surfaces.

:51. ln a projectile, the combination. with a delayY action train.` a percussion device operable upon impact of the projectile with water to ignite said train. of means for producing almost instantaneous explosion of the. projectile, said means being normally out ol' operative position but being arranged to he brought into operative position b v motion ol the projectile in lliglit. said means moreover being operable onlyY by impact ol" the projectile with solid material.

13;). [firing mechanism l'or projectiles conipi'isiiig the combination, with a delay action train, movable, igiiitiiig means normally in inoperative. position but capable when in operative position of igniting said delay train upon impact ot' relatively low intensity. ot movable, train-shortening means normally in inoperative position but capable when in operative position of shortening said delay train upon impact ot' an intensity greater than that sullicing to ignite said traiin both said igniting means and said traiii-shortening means being arranged to be moved :intoniatieally into operative position by motion ol' the projectile in lliglit.

ln testimony whereotl l have signed this speciliration in the presence oli two subscribing witnesses.

illiliHl h'. lHllM.

Vtlitnesses:

N. C. Moiisn, Jam-1s H. Mann. 

